In the past (more than 50 years ago), impression molding was done on the eye using a plaster-like substance. A “positive” image was made from the mold using more plaster. A lens was then created by vacuum sealing plastic to the positive mold. A significant amount of time was then spent in post processing of the optics and fit adjustments. The lens did not breathe oxygen and could not be worn very long. In addition, there were problems with this process including shrinking of the mold as it dried, which created a shape very different from the actual eye. Current breathable plastics cannot be vacuum molded.
All contact lens designs currently utilize a series of curves, which approximate the average ocular surface. There are no contact lenses custom fit based on the actual surface of the eye. At this time, all ocular surface evaluation data comes from expensive digital imagery equipment and gives information on a limited surface area, requiring extrapolations of curvatures and prevents customized micro-changes of the posterior contact lens surface.
Scleral contact lenses (large diameter lenses) comprise a subset of gas permeable (GP) contact lenses and completely vault the cornea, landing instead on the scleral part of the eye. Although the original glass scleral contact lenses were first fit in the 1930s, and later molded plastic scleral lenses on the 1950s and 1960s, it was not until the late 1990s that material advancements made their clinical use practical and physiologically tolerable.
Currently available scleral lens are at best semi-custom, and require subjects to sit for extended fitting sessions performed by specialized contact lens eye care providers. Many who suffer from corneal and ocular surface disease are not located near a specialist and incur pricey and repeated travel expenses. These factors are barriers for subjects with corneal disease, and many reach a point where treatment options and visual corrections become very limited.
There is a significant need for a highly customizable oxygen-transmitting device, which follows the contours of an individual eye.